Synthesis and characterization of arabinoxylan-bis[2-(methacryloyloxy)ethyl] phosphate crosslinked copolymer network by high energy gamma radiation for use in controlled drug delivery applications

Bone-like apatite formation in biocompatible phosphate-crosslinked bacterial cellulose-based hydrogels for bone tissue engineering applications

Addressing major bone injuries is a challenge in bone regeneration, necessitating innovative 3D hydrogel-based therapeutic approaches to enhance scaffold properties for better bioactivity. Bacterial cellulose (BC) is an excellent scaffold for bone tissue engineering due to its biocompatibility, high porosity, substantial surface area, and remarkable mechanical strength. However, its practical application is limited due to a lack of inherent osteogenic activity and biomineralization ability. In this study, we synthesized bone-like apatite in biocompatible BC hydrogel by introducing phosphate groups. Hydrogels were prepared using fibrous BC, acrylamide (AM), and bis [2-methacryloyloxy] ethyl phosphate (BMEP) as a crosslinker through free radical polymerization (P-BC-PAM). P-BC-PAM hydrogels exhibited outstanding compressive mechanical properties, highly interconnected porous structures, good swelling, and biodegradable properties. BMEP content significantly influenced the physicochemical and biological properties of the hydrogels. Increasing BMEP content enhanced the fibrous structure, porosity from 85.1 % to 89.5 %, and compressive mechanical strength. The optimized hydrogel (2.0P-BC-PAM) displayed maximum compressive stress, toughness, and elastic modulus at 75 % strain: 221 ± 0.08 kPa, 24,674.2 ± 978 kPa, and 11 ± 0.47 kPa, respectively. P-BC-PAM hydrogels underwent biomineralization in simulated body fluid (SBF) for 14 days, forming bone-like apatite with a Ca/P ratio of 1.75, similar to hydroxyapatite. Confirmed by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM), this suggests their potential as scaffolds for bone tissue engineering. MC3T3-E1 osteoblast cells effectively attached and proliferated on P-BC-PAM. In summary, this study contributes insights into developing phosphate-functionalized BC-based hydrogels with potential applications in bone tissue engineering.

Design and development of pH-responsive alginate-based nanogel carriers for etoposide delivery

Recently, pH-responsive nanogels are playing progressively important roles in cancer treatment. The present study focuses on designing and developing pH-responsive alginate-based nanogels to achieve a controlled release of etoposide (Et) while enhancing its hydrophilicity. Alginate (ALG) is grafted with 2-hydroxypropyl methacrylamide (HPMA) through a microwave-supported method, and the chemical structure of the graft copolymer (ALG-g-PHPMA) was verified by 1H/13C NMR and FTIR techniques. The ALG-g-PHPMA and anticancer drug-loaded ALG-g-PHPMA@Et nanogels were obtained using an emulsion method, and their structures were characterized through FTIR, TG/DSC, AFM/TEM, BET, and DLS analyses. The ALG-g-PHPMA nanogels demonstrated a good drug encapsulation efficiency (79.60 %), displaying a pH-dependent release profile and an in vitro accelerated release of Et compared to the ALG nanogels. Thermal and BET analyses revealed enhanced stability, surface area, and porosity volume of the alginate nanogels. The grafting of PHPMA chains onto alginate altered the surface topology of the ALG nanogels, resulting in lower surface roughness. Furthermore, cytotoxicity tests showed the high biocompatibility of the ALG-g-PHPMA copolymer and its nanogels. The ALG-g-PHPMA@Et nanogels exhibited a higher anticancer effect on lung cancer (H1299) cells than free etoposide. These results suggest that the ALG-g-PHPMA nanogels can be applied as a pH-dependent nanoplatform for delivering anticancer drugs.